Solar and Planetary Astronomy

Solar and Planetary AstronomyThe Sun is located at around eight light minutes distance. It is considered a rather stable star, apart from the 11 years cycle of its sunspots. These are the low temperature regions on the Sun’s surface, due to the magnetic activity. The luminosity of our star increased with 40% since its inception.

The layers of the Sun are photosphere, chromospheres and super heated corona. The photosphere is the outer surface, the chromospheres the thin region that makes transition to the regions with high temperatures. The core region is at the centre of the Sun, where the nuclear fusion takes place. Around it, the radiation zone is the birth place of the plasma, that emerges to the surface in the form of explosions and solar winds. These particles emerge from the sun to the Solar system and heliopausa. The Earth’s two poles retrieve these events as aurora borealis.

The planetary science looks at assemblages of asteroids, comets, dwarf planets, moons and planets that both orbit the sun or the extrasolar regions. Although the current array of planets in our solar system is already well understood, new discoveries are made every day.

The current known Solar System is divided into inner planets, asteroid belt and outer planets. Mercury, Venus, Earth and Mars are the inner terrestrial planets, while Jupiter, Saturn, Uranus and Neptune are the outer gas giants protecting the other planets from the asteroids in the Kuiper Belt and the Oort Cloud, that are supposed to be at a distance of one light year.

Planets are usually formed with methods such as collision, gravitational attraction and accretion from an initial protoplanetary disk. The matter that did not stick to the planetary mass was expelled with the help of radiation pressure and solar wind. The process of retaining or expelling matter has a proof on the impact craters that are usually observed on the surface of the moons orbiting the planets or becoming the actual clutters that formed the moons. A similar hypothesis is formed for the birth of the Earth’s Moon.